There is a growing need for electrical connections where conductive elements such as electrical connectors, circuit boards, and electronic modules located on each major side of a circuit board must be connected with each other and with the circuit board. U.S. Pat. No. 6,413,119, to Gabrisko, Jr. et al., which is incorporated herein for background purposes, discloses a filtered electrical connector, in which conductive pins (shown at 20) extend through a first circuit board (filter insert shown at 22) for connection with a mating connector on a first side and a second circuit board on a second side apposing the first side.
The above cited '119 patent discloses an electrical connection having a filter insert (shown at 22) comprising a plated thermoplastic substrate (generally shown at 48) which exhibits an-isotropic thermal expansion properties and includes electrical devices (such as capacitors shown at 64) connected with the filter insert. The major lengths of these electrical devices are oriented along a direction of reduced thermal expansion properties of the substrate. It should be noted that a terminal may be press-fit into a plated through-hole in a circuit board to produce this type of connection.
As packaging sizes and distances between centerlines continue to decrease, and as manufacturers seek to reduce costs, however, there is an increasing need for systems and methods for providing connections, whereby normal forces and stresses that are incurred during production (e.g., during insertion), which may cause damage or fatigue to, for example, circuit traces, solder joints, and electronic components. Stresses, such as those that may be created among a terminal and a circuit board, may also impose constraints on the designs of such devices, particularly when the devices and their connections are to be subjected to harsh environments, such as those found in vehicles (e.g., automobiles, aircraft, and the like), in heavy machinery or other high stress, shock-prone applications. Such design difficulties may also inhere in applications where size and/or weight is a significant factor (e.g., medical instruments). It should also be noted that cast contact pins in a connector housing may be force-fit into plated molded holes in the filter insert to establish good electrical contact for grounding the filter insert.
It should be noted that one advantage of such as a filtered insert substrate is that an-isotropic properties of the substrate material may be utilized to decrease the undesirable impacts (e.g., thermal expansion, stresses resulting from harsh environments) may impose on interference-fit connections (e.g., among one or more conductive pins and a circuit board, among one or more contact pins and a circuit board). Additionally, detailed features, such as holes configured for connection with electrical ground, may be molded into the material.
Despite these advantages, however, presently known approaches typically entail relatively high cost and complexity. For example, the requisite plating processes, the necessary use of an-isotropic thermoplastic materials, and their associated materials and tooling all typically contribute to increased complexity and cost.
It would therefore be beneficial to have a system and method that would enable use of low cost circuit board substrates, such as an FR-4 epoxy glass laminate having circuit traces and plated through-holes and produced through conventional plating processes, in applications whereby conductive elements located on a first major side of a circuit board may be inter-connected with the circuit board and with conductive elements located on a second major side of the circuit board. It would further beneficial to have a system and method that would provide electrical grounding of a circuit board, despite poor ground solderability characteristics, with reduced cost and increased reliability. It would further be desirable to have a system and method whereby such grounding, and any connections involved in such system and method, could be accomplished with significantly reduced, or eliminated, insertion forces, whereby normal forces and stresses that damage circuit traces, solder joints, and electronic components, might be reduced or eliminated.